fix(scanner): preserve dirty usage convergence (#3844)

Co-authored-by: Henry Guo <marshawcoco@users.noreply.github.com>

crates/scanner/src/scanner.rs

@@ -124,6 +124,10 @@ enum ScannerCycleWakeReason {
 }
 
 async fn wait_for_next_scanner_cycle(ctx: &CancellationToken, delay: Duration) -> ScannerCycleWakeReason {
+    if dirty_usage_buckets_pending() {
+        return ScannerCycleWakeReason::DirtyUsage;
+    }
+
     let sleep = tokio::time::sleep(delay);
     tokio::pin!(sleep);
 
@@ -1624,6 +1628,19 @@ mod tests {
         crate::scanner_io::clear_dirty_usage_bucket("photos");
     }
 
+    #[tokio::test]
+    #[serial]
+    async fn test_wait_for_next_scanner_cycle_sees_existing_dirty_usage() {
+        crate::scanner_io::clear_dirty_usage_bucket("photos");
+        crate::scanner_io::record_dirty_usage_bucket("photos");
+
+        let ctx = CancellationToken::new();
+        let reason = wait_for_next_scanner_cycle(&ctx, Duration::from_secs(60)).await;
+
+        assert_eq!(reason, ScannerCycleWakeReason::DirtyUsage);
+        crate::scanner_io::clear_dirty_usage_bucket("photos");
+    }
+
     #[test]
     #[serial]
     fn test_get_cycle_scan_mode_runs_deep_until_selection_window_completes() {